Despite well‐matching indoor illumination spectra, the performance of wide bandgap perovskite solar cells (WB‐PSCs) for indoor photovoltaics (i‐PV) is hindered by photo‐induced halide phase segregation and trap‐assisted non‐radiative recombination. Herein, a Triple Passivation Treatment (TPT) reassembly strategy is presented to simultaneously suppress bulk and surface defects. TPT induces a transition in perovskite surface energetics from n ‐type to p ‐type and remarkably increases the photoluminescence quantum yield from 0.5 to 2.1%, creating a more favorable band alignment for hole extraction whilst substantially reducing halide phase segregation. As a result, 1.75 eV WB‐PSCs achieve an indoor Power Conversion Efficiency (iPCE) of 37.6% under 1000 lux illumination. Under standard sunlight conditions, the devices reach a Power Conversion Efficiency (PCE) of 20.1% and a fill factor of 78.5%, among the best performance parameters for this bandgap. Importantly, the passivated devices exhibit excellent shelf stability, retaining 92% of their initial performance after 3200 h. Under ambient air conditions at 55 °C, the unencapsulated devices maintained 76% of their initial PCE after 300 h continuous light soaking. The findings represent a significant breakthrough in the development of stable WB‐PSCs for i‐PV applications, with minimized nonradiative losses and enhanced performance.